Conversion of hydrocarbons



Oct. 17, 1944. 1 EGLOFF 2,360,553

CONVERSION OF HYDROCARBONS Filed Feb. 28, 1941 TRACT/UNA T03'szzwle/lrlzve CHAMBER JET/16770)]! CHHMBEB FURNHCE v I I:

1772 ue77Za7 Patented Oct. 17, 1944 UNITED. .STATES PATENT :oFFlcECONVERSION OF HYDBOCARBONS Gustav Egloii, Chicago, 111., assignor toUniversal Oil Products Company, Chicago, 11L, a corporation of DelawareApplication February 28, 1941, Serial No. 380,973

3 Claims. '(Cl.196-52) This invention relates to a process for theconversion of hydrocarbon oil into lower boiling hydrocarbons includinggasoline. More speciflcally, it relates to a cracking process employingpowdered catalyst in which the hydrocarbon oils may be converted in atwo-stage operation into motor fuel of high antiknock quality and highlead susceptibility.

High temperature catalytic cracking, a term usually employed forcatalytic cracking conducted in the temperature range of fromapproximately'850 to 1000 F., ordinarily produces gasoline boiling rangehydrocarbons withantiknock ratings of from 76 to 80 Motor method which.are very valuable either for direct use as motor fuels or {or use asblending agents. Because of the relatively high olefin content, however,the motor fuel so produced may have only a moderate lead susceptibilityand may therefore be unsuitablefor some purposes. On the other hand, lowtemperature catalytic cracking, a term usually employed forcatalytic-cracking conducted in the range of from approximately 700 to850 it, produces a substantially saturated gasoline of lower initialoctane rating but of higher lead susceptibility than the hightemperature process. However, the rate of conversion in the.

spent catalyst from a low temperature step, and

p the conversion products from the high temperature step are contactedwith fresh catalyst in the lower temperature step. In'this manner, ahighly saturated gasoline may be produced, and at the same time, theadvantages or high temperature catalytic cracking may be retained.

In one specific embodiment the invention comprises supplying a heatedhydrocarbon oil ,charge together with heated insufliciently convertedhydrocarbons formed as hereinafter set forth and.

containing powdered catalyst to a primary con- ,version zone, separatingthe resultant nonlow temperature range is considerably less than that inthe high temperature range so thatvthe reactor sizes, etc., for lowtemperature cracking must be considerably larger for the samethrough-put.

Cracking conducted in the presence ofa catalyst is accompanied by, thedeposition of a carbonaceous substance upon the catalyst which,

as it accumulates, results in a decrease in the ability of the catalystat constant temperature,

' catalyst than was obtained at the lower temperature with the freshcatalyst. I

The purpose of this invention is, therefore, to provide a combinationhigh temperature-low temperature powdered catalyst cracking process inwhich the fresh charge is converted in a high vaporous conversionproducts containing, spent catalyst from the vaporous conversionproducts. recovering said non-vaporous conversion products containingspent catalyst, contacting said vaporous conversion products with freshor fresh- 1y regenerated powdered catalyst in a secondary conversionzone, separating the resultant insufficiently converted hydrocarbonscontaining catalyst from the desired products including gasoline boilingrange hydrocarbons, recovering saiddesired products, and returning saidinsufllcien'tly converted hydrocarbons containing catalyst" to said.primary conversion zone as hereinbefore set forth. r

' The accompanying drawing diagrammatically illustrates in sideelevation one specific arrangementcf-apparatus'which may be employed forcarrying out the process of this invention.

Referring now to the drawing, charging oil, which may compriseheavynaphtha, kerosene, gas oil, or any other petroleum distillate or mixturethereof, is introduced through line l,valve r m 3, line 4, and valve 5into heating coil 8 wherein it is heated to a temperature of from 600 to1200" E, preferably from 850 to 1000 E.

and at a pressure of from slightly superatmospheric to 500 pounds ormore per square inch.

heat being supplied by means of furnace 'l. The

resultant heated material is conducted through with insuiilcientlyconverted hydrocarformed as hereinafter described and conline giarndvalve 8 into line ll wherein it is com in taining catalyst. The catalystand hydrocarbon mixture i introduced into reaction chamber I..-

or at a slightly reduced pressure and temperature relative to, thatemployed at the outlet of. temperature step in the presence f, partiallyas heating coil 8, andis preferably insulated to reduce radiation lossestherefrom, although noinsulation appears in the drawing. The conversionproducts from chamber ",con-

taining the catalyst, are withdrawn through line H and valve l2 intoseparating chamber I! wherein a non-vaporous residual oil containingsaid catalyst is separated from the vaporo-'s conversion products and iswithdrawn through line II and valve II. Separating chamber ll may bemaintained at substantially the same temperature and pressure asreaction chamber II, but is preferably maintained at atemperature offrom 600 to 900 F. ,and at a pressure of from substantially atmosphericto 200 pounds or more per square inch superatmospheric. The vaporousconversion products from chamber II are with-' drawn through line It andvalve I1 and are thereafter commingled with fresh catalyst intro-- ducedthrough line l8, valve l8, pump 20, line 2|, and valve 22.. The freshcatalyst introduced at this point may be heated to substantially thesame temperature as that of the vaporous conversion products leavingchamber 13, although no provision for heating is shown in theaccompanying drawing, and may, if desired, be admixed with a smallproportion of the fresh charging stock, or with a small proportion of anaphthenic oil.

The resultant mixture of catalyst and conversion products is introducedthrough line 28 into reaction chamber 24 which is preferably maintainedat substantially the same temperature and pressure as, or at a slightlyreduced temperature and pressure relative to, that employed in chamber13 and which may be insulated to reduce radiation losses therefrom,although no insulation appears in the drawing. The conversion productscontaining catalyst are withdrawn through line 25 and valve 26 andsupplied to fractionator 21 wherein heavy reflux condensate conolineboiling range. hydrocarbons may be separated. The gasoline boiling rangehydrocarbons are withdrawn through line 28 and valve 28 and may. becooled, condensed, and separated from light gases by well known means,not shown. A.

portion of the gasoline boiling range hydrocarbons may be returned bywell known means, not

shown, to fractionator 21 as a cooling and refluxing medium and theremaining portion is withdrawn as a product of the process. Fractionator21 is maintained at substantially the same or at a reduced pressurecompared to that employed in chamber 24.

Light reflux condensate may, if desired, be condensed and separated infractionator 31 and withdrawn through line and valve 3|. some cases,however, it may be desirable to recycle all the insufliciently convertedoils sepa j.

rated in fractionator 21. The heavy reflux con densate containing thecatalyst is withdrawn from fractionator 21 through line 82 following;

which a portion thereof may be removed through valve 33. The remainingportion, or, if desired, all of the heavy reflux condensate may besupplied through line 34, valve 35, pump 88, line 31, and valve 88 intoheating coil 30 wherein'it may be heated with or without substantialcracking,

' heat being supplied by furnace 40. The temperature of the materialleaving heating coil 39 may range from 600 to 1200 F., preferably from850 to 1050 R; and the pressure may range from slightly'superatmospheric to 500 pounds or more per square inch. The productsfrom heating coil 30 are directed through line 4| and valve 42 and arethereafter commingled with the material 75' leaving heating coil 6, andthe mixture is supplied to reaction chamber III as hereinbefore setforth.

The catalyst which may be used in this process maycomprise any adsorbentmass, either natural or synthetic, which is known to promote thecracking reaction and which may be prepared in a finely divided form.The preferred catalyst comprises substantially hydrous silica compositedwith anhydrous alumina and/or hydrous zirconia, and may be prepared bythe general procedure of separately precipitating or co-precipitatingsilicon, aluminum, and/or zirconium hydrous oxides from suitablecompounds, and drying the resultant mixture at temperatures of from 800to 1500 F., following which the mass is ground to a finely dividedstate. The spent catalyst which is removed from separating chamber l3and contained'in the non-vaporous residuum may be separated therefrom byany suitabie means, such as flashing, filtration, etc., and may beregenerated by oxygen=containing gases at an elevated temperature, bysolvent extraction, or by any other suitable method, and returned to theprocess for further use.

The following example is intended to be used only as an illustration ofthe process; consequently, the invention is not to be limited to theconditions thereof.

A Mid-Continent 33 A. P. I. gravity gas oil is heated to a temperatureof 900 F., at a pressure of 100 pounds per square inch, and the heatedoil is commingled with insufliciently converted hydrocarbons formedashereinafter set forth and containing catalyst. The mixture isintroduced into areaction zone maintained at a temperature and pressuresufficient to effect cracking.

suflicient residence time and are supplied to a separating chambermaintained at approximately 825 F. and pounds pressure wherein anonvaporous residue containing spent catalyst is separated from thevaporous conversion products and withdrawn, The vap'orous conversionproducts are withdrawn from the separating chamber, commingled withfresh powdered. catalyst which has been heated to approximately 825 F;and the resulting mixture is introduced to a reaction chamber maintainedat approximately 800 F. and 65 pounds pressure. The products arewithdrawn and fractionated to separate insufficiently convertedhydrocarbons containing the catalyst from gasoline and light gases. Theinsufficiently converted hydrocarbons containing the-catalyst arewithdrawn from the ractionator, heated to a temperature of 950 F. at apressure of pounds, and are commingled with the heated charge ashereinbefore set forth.

When this process is operated according to these conditions, one mayobtain a 65% yield of 400 F. end point gasoline with a Motor methodoctane number of 76, which on the addition of 3 cc. tetraethyl lead pergallon of gasoline has an 88 octane number. Approximately 65% of thegasoline boils below 300 F. and has 9. Motor method octane number of'17, which on the addition of 3 cc. tetraethyl lead per gallon ofgasoline increases to 90. Both the 400 end point and line oi relativelyhigh olefin content. separating from the resulting conversion productsnonvaporous residue containing the suspended catalyst and cracked vaporsincluding said oleiinic gasoline, mixing a fresh catalyst with saidcracked vapors including the oleilnic gasoline without prior intentionalcooling of the cracked vapors and continuing the conversion at acracking temperature below that of the first-mentioned conversion stepto produce gasoline substantially iree oi oletlns', separating thesubstantially olefin-free gasoline from insufliciently cracked productscontaining the suspended catalyst and returning at least a portion 0!the latter to the first-mentioned conversion step as the source 01 saidpartially spent catalyst and toe!- ,iect further conversion of saidinsufllciently cracked products.

8. The process or claim 1 further characterized in that said-hydrocarbonoil and the insufilciently cracked products containing the suspendedcatalyst are independently heated to a conversion temperature, theheated oils combined and the mixture introduced to a reaction zone inwhich conversion is eiiected without the further addition of heat.

3. A process for the conversion of hydrocarbon oil which comprisessubjecting the oil to catalytic cracking in the presence of a partiallyspent powdered cracking catalyst at a cracking temperature regulated toefiect conversion of said oil into gasoline containing a substantialamount oi oleflns, separating cracked vapors including .the oleflnicgasoline from the catalyst and residue, subjecting the cracked vaporswithout prior intentional cooling thereof to continued conversion in thepresence of a fresh powdered cracking catalyst under deoleflnizlngconditions to produce a gasoline substantially free' of oleflns,

separating the substantially olefin-tree gasoline from heavierconversion products and catalyst, supplyin the latter to the firstmentioned conversion step as said partially spent'catalyst, andsupplying at least a portion of said heavier conversion products to thefirst mentioned conversion step for further treatment therein.

GUSTAV EGLOFF.

